Presenter:

Wan Kyu Park(National High Magnetic Field Laboratory, Florida State University)

Authors:

Wan Kyu Park(National High Magnetic Field Laboratory, Florida State University)

Shu Liu(National High Magnetic Field Laboratory, Florida State University)

Laura Greene(National High Magnetic Field Laboratory, Florida State University)

D.J. Kim(Department of Physics and Astronomy, University of California - Irvine)

Zachary Fisk(Department of Physics and Astronomy, University of California - Irvine)

Samarium hexaboride (SmB6), a well-known Kondo insulator, has recently received great deal of attention due to the possibility of being a correlated topological insulator. Despite numerous experimental findings supportive of this possibility, its detailed spectroscopic properties remain to be elucidated. Our recent tunneling spectroscopy based on planar junctions on SmB6 [1, 2] has not only found evidence for the existence of multiple surface Dirac fermions, in agreement with a quantum oscillation study as well as theoretical predictions, but also revealed their intriguing topological nature affected by the interaction with bulk excitations, called spin excitons [3]. We will present tunneling conductance spectra for two different surface orientations as a function of temperature and magnetic field and discuss the implications of our results. In particular, we will focus on some of the outstanding open questions in relation to our findings. [1] W. K. Park et al., Proc. Natl. Acad. Sci. U. S. A. 113, 6599 (2016); [2] L. Sun et al., Phys. Rev. B 95, 195129 (2017); [3] G. A. Kapilevich et al., Phys. Rev. B 92, 085133 (2015).